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Lund University


Biology library guide to information searches

Block search

Block search is a method to structure your search. You need to use a search tool that understands search operators (AND/OR/NOT) and preferably allows you to use different lines for searching (i.e. a bibliographic database).


Step 1. Identify the different concepts that you would like your search results to include.


Research question Concepts
Does climate change effect bird migration? climate change, bird, migration
Is mycorrhiza effected by clearcutting in boreal forests? clearcutting, boreal forest, mycorrhiza
How does bacteria interact with myeloid cells to manipulate their function? bacteria, myeloid cells, manipulation
Is aquatic biodiversity affected by climate change? aquatic, biodiversity, climate change


Step 2. Put the different concepts on different lines (=blocks) with AND in between.

If you can't see the different lines you may have to go to "advanced search". Example:

Block 1 aquatic
Block 2 biodiversity
Block 3 "climate change"

In the search tool, it may look something like this:

block search


Step 3. Add synonyms, alternative expressions, spelling variants etc. on each line/block with OR.

Don't forget truncation and phrase search! Example:

Block 1 aquatic* OR lake* OR limn* OR marine OR ocean* OR freshwater* OR river*
Block 2 biodiversit* OR diversit* OR "genetic variation*" OR "species richness*"
Block 3 "climate change*" OR "global change*" OR "global warming*" OR "greenhouse effect*"

Structuring your search like this is a way of telling the search tool that you want all results to include at least one thing from block 1, at least one thing from block 2 and at least one thing from block 3.

Parentheses instead of lines

An alternative to using lines is to put each "line" within parentheses. However, when doing advanced searches it is easy to put a single parenthesis wrong which will mess up your whole search. We suggest you stick with the lines if you can (however not all search tools have the option of lines). Example:

(cat OR feline) AND (behavior OR behaviour OR etology)

Common mistake

If you get strange results it is likely that you have forgotten a search operator. For example, if you search for:

(cat OR feline) AND (behavior OR behaviour etology)

You forgot an "OR" between behaviour and etology. What you are really searching for is:

(cat OR feline) AND (behavior OR behaviour AND etology)

This means that etology must be in all results, reducing the number of results dramatically.